In recent years 5G NR (New Radio) and long-term evolution (LTE)systemic steadily emerging to meet desired data rate and QoS. The emerging applications like IoT demands datarich services and sophisticated server related applications with reduced latency measures. In this paper introduces variable rate coded OFDM system, optimal channel estimation, multi user detection (MUD) and MIMO pre-coding to meet the 5Gsystem requirements. In this work, we also analyze both performance metrics and vulnerability of 5G NR over different channel conditions. The proposed system includes OFDM and error correction with the combined convolution codes (CE) and reed Solomon codes and improved diversity gain with parameters chosen to meet 5G NR wireless standards. The SNR requirements at the base station to achieve 95% of the maximum throughput specified for fixed reference channels are the subject of this paper's analysis and discussion of the receiver reference sensitivity requirements for 5G New Radio (NR) wireless communications systems. A wide range of different transmission bandwidths and radio interface numerologies are investigated at sub-6GHz and millimeterwave frequency ranges, covering both AWGN and fading channel scenarios as well as various mobility conditions, based on the most recent 3GPP specifications and evaluation assumptions agreed upon for Release. The performance results utilizing the LDPC coding scheme are shown and examined, and results using LTE turbo code are also supplied for comparison. Performance results are measured in terms of relative throughput and block error rate. According to the findings, LDPC code consistently outperforms turbo code in terms of reference sensitivity and UL radio link performance in frequency-selective channels. The results further show that the purely front-loaded demodulation reference signal (DM-RS)-based system can perform better than the corresponding two DM-RS-based system even at greater velocities and high center frequencies, enabling minimal decoding latency and effective pipelined receiver processing.